If you wish to install Lync 2013 Preview on Windows 2012 RC, here is an easy way to prep your Front End server:
Download “LyncFeatures.xml” and place it on C:\
On your server, start PowerShell as Administrator and run the following:
$x = Import-Clixml C:\LyncFeatures.xml
$x | Add-WindowsFeature
Reboot when done and proceed with Lync 2013 installation.